Experimental study on combustion and emissions of an SI engine with gasoline port injection and acetone-butanol-ethanol (ABE) direct injection

Using ABE instead of bio-butanol as an alternative fuel can reduce the costs of separating and purifying bio-butanol from ABE solution. This paper investigated the performance of an SI engine with gasoline port injection plus ABE direct injection (GPI + ABEDI) at different ABE direct injection ratio (ABEDIr), excess air ratio (lambda) and DIT. Results show that, with increasing ABEDIr, IMEP basically increases continuously at lambda = 0.9 while increases firstly and then decreases at lambda = 1.0 to 1.3. The highest IMEP is 7.3%, 5.2%, 3%, 2.8% and 3.7% higher than that of gasoline at lambda = 0.9 to 1.3. CA0-10, CA0-90 and CoVIMEP with ABE addition are lower than that of gasoline, and minimum CA0-90 value is 6.9%, 11.2% and 18% lower than that of gasoline at lambda = 0.9, 1.0 and 1.3. HC emissions decrease initially and then increase as ABEDIr increases, and ABEDIr and DITs corresponding to lowest HC emissions are concentrated at 20%, 40%, 60% and 300-210 degrees CA BTDC, respectively. NOx emissions of 75 degrees CA BTDC are the lowest while pure ABE with early DIT owns lower CO. Nucleation mode, accumulation mode and total particle number (TPN) decrease initially and then increase as ABEDIr increases. 40% or 60% of ABEDIr with 300 and 255 degrees CA BTDC of DIT are superior for lowest particle number (PN), and the lowest TPN is 99.9%, 99.9%, 99.6%, 96.6% and 90% lower than that of gasoline at lambda = 0.9 to 1.3, respectively. In summary, GPI + ABEDI mode adopting 80% of ABEDIr combined with DIT = 300 degrees CA BTDC can effectively improve combustion and emissions.

Automated summary

This study investigated the performance of using ABE direct injection as an alternative to bio-butanol in an SI engine. Results showed that, under specific ABEDIr and lambda, it can effectively improve IMEP, reduce HC and NOx emissions, and decrease particle numbers.